THz Laser Chip Sets Power Records

Photonics SpectraMay 2014
LEEDS, England, Feb. 19, 2014 — A newly developed terahertz laser chip is already setting records as the most powerful in the world.

A team from the University of Leeds has engineered a quantum cascade terahertz laser that exceeds 1-W output power, more than doubling landmarks set previously by the Massachusetts Institute of Technology and, more recently, by researchers in Vienna.

Terahertz waves can penetrate materials that block visible light and have applications ranging from chemical analysis to security. However, a main challenge is making the lasers powerful and compact enough to be useful. The lasers developed at Leeds are a few square millimeters in size.

A computer-generated image of the world's most powerful THz laser, developed by the University of Leeds. Courtesy University of Leeds.
“Although it is possible to build large instruments that generate powerful beams of terahertz radiation, these instruments are only useful for a limited set of applications,” said Edmund Linfield, professor of terahertz electronics at the university’s School of Electronic and Electrical Engineering.

The researchers developed multilayer semiconductors such as gallium arsenide one atomic monolayer at a time. They controlled the thickness and composition of each individual layer and created semiconductor materials of between 1000 and 2000 layers, Linfield said, which resulted in the new laser chip’s record power.

Potential applications for the tiny chip include monitoring pharmaceutical products, remote sensing of chemical signatures of explosives in unopened envelopes, telecommunications and noninvasive detection of cancers in the human body.

The research was funded by the Engineering and Physical Sciences Research Council, and has been published in Electronics Letters.

Electromagnetic radiation with frequencies between 300 GHz and 10 THz, and existing between regions of the electromagnetic spectrum that are typically classified as the far-infrared and microwave regions. Because terahertz waves have the ability to penetrate some solid materials, they have the potential for applications in medicine and surveillance.